Yahara Portal

Explore the legacy and future of the Yahara Lakes and Watershed

Eurasian Water Milfoil


Eurasian Water Milfoil (Myriophyllum spicatum) is a submersed aquatic plant native to Europe, Asia and northern Africa. It is one of eight milfoil species found in Wisconsin and the only one non-native to the state. It first showed up in Wisconsin's counties in the 1960's and in the past three decades, has expanded its range to about 310 lakes including all of the lakes in the Yahara Watershed. 

Problems associated with this invader

Because of its potential for explosive growth and its incredible ability to regenerate, Eurasian milfoil can successfully out-compete most native aquatic plants, especially in disturbed areas. In a number of Wisconsin lakes, Eurasian milfoil has formed huge monoculture stands with vast mats of surface foliage that shade-out native aquatic plants and diminish the aesthetic beauty. Recreational activities like swimming, boating and sport fishing are also diminished on Wisconsin lakes infested with Eurasian milfoil. 


  • Submersed, rooted aquatic plant in shallow waters (less than 30 feet deep)
  • Long branching stems near the surface with soft, feathery leaves
  • Leaves usually attached in whorls of four, but sometimes 3 or 5. Each leaf has 10-21 pairs of leaflets 
  • Leaflets are usually closely-spaced
  • Leaves are limp when out of water
  • Top of plants often turn red; Small reddish flowers in mid-summer
  • Plants can grow up to 15 feet long


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